This invention relates to new azoalkanes containing isothiocyanate or isocyanate groups in the .alpha.-position to the azo group. The compounds can be symmetrical azoalkanes with isothiocyanate or isocyanate groups in the .alpha. and .alpha.'-positions, unsymmetrical t-alkyl (where " t" designates tertiary), cycloalkyl and aralkyl azoalkanes containing one isothiocyanate or isocyanate group .alpha. to an azo group, and unsymmetrical .alpha.-cyanoazoalkanes containing one isothiocyanate or isocyanate group in the .alpha.'-position. In addition, this invention relates to the corresponding derivatives of these compounds, for example, by reaction with active hydrogen compounds such as ammonia, amines, alcohols, phenols, thiols, diols, dithiols, diamines, hydrazine derivatives and the like. The compounds are efficient foaming agents for polyester resins.
As far as is now known, no azoalkanes of general structure I hereinbelow have been previously reported, although various patents have disclosed or claimed t-alkyl, cycloalkyl and aralkylazoalkanes containing one .alpha.-chloro, .alpha.-cyanate or .alpha.-thiocyanate group (British Pat. No. 1,272,284), and symmetrical .alpha.,.alpha.'-dicyanato (or dithiocyanato)-azoalkanes and unsymmetrical .alpha.-cyano-.alpha.'-cyanato (or thiocyanato) -azoalkanes (U.S. Pat. No. 3,282,912 and Canadian Pat. No. 750,380). Aromatic azos containing .alpha.-isocyanato groups are reported in Angew. Chemie., International Ed. Vol. 7, 293-4 (1968).